1. Field of the Invention
This invention relates to improved contaminant detection and labeling compositions and a method for testing material, parts and assemblies to locate and identify surface contaminants. The invention is especially concerned with a novel, extremely economical water-based, stable and sensitive contaminant identifier composition and a developer composition employing as solvent or vehicle, essentially a biodegradable nonionic surfactant in the form of mixtures of certain ethoxylated alcohols and water; and to a method utilizing such compositions for revealing surface contamination on parts and assemblies.
2. Description of Background Art
Many inspection methods for location and evaluation of surface flows or cracks in test bodies or parts are known. In such systems, a highly penetrating dye-bearing composition, is used which will penetrate the openings of the surface cracks or flaws in the part and the excess penetrant composition is removed from the surface of the body. A developer composition may then be applied to the part surface, which acts as a wick and causes the liquid penetrant containing the fluorescent dye, which was retained in the cracks or surface flaws, to be drawn up out of the surface defects by capillary action. The part is then exposed to appropriate lighting conditions, such as ultraviolet light, and the location of the flaws is revealed by the emission of visible fluorescent light by the penetrant dye which was retained in the cracks or flaws after the penetrant compositions was moved from the surface of the part.
Such inspection methods were directed to detecting flaws formed within test bodies or parts, and the formulations utilized and the method employed do not identify the presence of and specific locations of surface-born contaminants such as silicone and petroleum or other oil based products which can readily interfere with processes such as penetrant inspection, painting and bonding as used throughout the aerospace industry. The contaminants if not detected and removed can prevent the penetrant inspection process from wetting the surfaces of parts and assemblies being inspected for defects such as cracks, and also prevent the paint and bonding processes from being effectively applied. In the case of the penetrant inspection process, contamination can prevent the disclosure of a defect which can cause a catastrophic failure in an aircraft, missile or space vehicle.